diff --git a/internal/modes/decoder.go b/internal/modes/decoder.go
index 80b65f2..e120abf 100644
--- a/internal/modes/decoder.go
+++ b/internal/modes/decoder.go
@@ -614,6 +614,7 @@ func (d *Decoder) decodeCPRPosition(aircraft *Aircraft) {
 	}
 
 	aircraft.Longitude = lon
+	aircraft.PositionValid = true
 
 	// CPR decoding completed successfully
 }